of macomb



June 17, 1930. 1 1,764,370

CHECK DRAFT DAMPER AND 500T ELIMINATOR ron HE'ATERS Filed 0431:. 10, 1929 Patented June 17, 1930 UNITED STATES PATENT orrics DONALD B. TOLLEY, OF MACOMB, ILLINOIS, ASSIG NOR TO AMERICAN STEEL PRODUCTS 00., F MACOMB, ILLINOIS, A CORPORATION OF ILLINOIS CHECK-DRAFT DAMPER AND SOOT ELIMINATOR FOR HEATERS Application filed October 10, 1929. Serial No. 398,770.

My invention relates to the type ofheaters in which a by-pass ductleads from the ashpit to the flue, and in which this duct is provided both with an air inlet and with damp ers respectively controlling the air inlet and the portion of the duct between this inlet and the flue. i

Heaters of this type have heretofore been provided with two conjointly acting (and sometimes integral) dampers for the above mentioned purposes. In such heater constructions, the duct-controlling damper is desirably pivoted at its lower end to the outward wall of the duct, so as to swing upwardly toward the inner face ofthat wall when this damper is opened. Thus arranged, the duct-controlling damper, when only partly open, slopes upwardly away from the duct Wall to which it is pivoted, thereby affording a trough adapted to catch both soot from the flue and coal which may accidentally have spilled into the check-draft chamber when the fuel for the heater was replenished. The coal or soot which is so caught between the damper and the pivoting flue wall is apt to block a wider opening of the same damper; and when this flue-controlling damper is rigidly connected to the inlet-controlling damper, such an action of the coal or soot 3 will also prevent the latter dam-per from closing the air inlet properly, so that the control arrangement can no longer function adequately.

In its general objects, my invention aims to overcome these objections by providing an auxiliary and movable discharge flap in the by-pass duct wall which will be opened automatically whenever the duct-controlling damper is moved to a position in which the cut is widely open, so that-any accumulations on the outer or upward face of the duct-controlling damper can drop out through aductopening which is closed by the said flap when the same damper is in a ductchoking posi- 4:; tion. I 7

Moreover, my invention aims to provide a simple and inexpensive arrangement for this purpose, and one in which gravity always tends to return both the dampers and the discharge flap to certain positions. Still further and also more detailed objects will appear from the following specification and from the accompanying drawings, in which Fig. 1 is a fragmentary vertical section through a coal-burning heater embodying my invention, showing the two dampers and the discharge flap in the positions whichthey occupy when the heater is relatively cool.

' Fig-. 2 is a section similar to a portion of Fig. 1 but with the two dampers andthe discharge flap in'their other extreme posipious, as occupied when the heater isiunduly i-ot.

Fig. 3 is a section along the line 33 of Fig.1.

Fig. 4 is an exterior elevation of the twin damper unit and the adjacent duct portions, drawn on a smaller scale than Figs. 1 to 3. In Fig. 1, the body of the heater is provided along one of its exterior walls 1 with a bypass duct 2 leading from the ashpit 3 to a,

check-draft chamber a underhanging the flue collar 5, this chamber beingconnected to the combustion chamber 6 of the heater by suitable passages (such as an aperture 7) through which the'combustion gases can pass from the combustion chamber to the flue 8.

The by-pass duct 2 is provided intermediate of its length, and desirably in its outward wall 9, with an opening 10, and a pivot shaft 11 extends across this opening parallelto the said outward wall at a considerable distance from both the upper and lower edges of the said opening. Pivoted on the pivot shaft 11 is a damper m'ember comprising a duct damper 12 adapted to extend substantially across the bore of the by-pass duct, andan inlet damper 13 adapted to close'the portion of the opening 10 which is below the pivot shaft. pivoted to the same duct wall 9 adjacent to the upper edge of the said opening 10, which flap swings downward by gravity and is adapted to close the part of the said opening above the pivot shaft. Y

Where the damper arrangement isto be automatically controlled in response to the temperature of thespace .in which the heater is used, as for example when it is used in a brooder, I make the upper or duct damper 12 Then I also provide a separate-flap 1 L heavier than the inlet damper 13, and desirably provide a weight extending inwardly from the inner face of the duct damper 12 to make the latter overbalance the combined weight of the inlet damper, the connecting link 16, and the lever 17 which is actuated thermostatically. For such actuation, I am here showing a thermally expansible wafer 18 interposed between this lever and a rigid bracket 19 extending outwardly from the bypass duct.

Then I also provide one of the members 12 and 14 with a nub. 20 projecting toward the other of these members for affording a minimum spacing between them, desirably by casting such a nub on the outer face of the duct damper 12.

Vvith my draft control thus arranged, the excessive weight of the weighted duct damper 12 causes the latter to extend substantially across the by-pass duct when the heater is relatively cool, as shown in Fig. 2, thus closing the by-pass from the ashpit to the flue. In this position, the inlet damper 13 extends away from the lower part of the opening 10,

thus permitting air to enter the duct below the duct dam 'er 12 and to pass downwardly into the ashpit 3 below the grate 21, so as to produce a down-draft for air supply through the grate.

When the temperature of the heater increases. the expansion of the thermostatic wafer 18 depresses the lever 17 (which is pivoted on a suspending bolt 22) and acts through the connecting link 16 to rock the damper member in a direction which is counterclockwise in Figs. 1 and 2, thereby gradually closing the inlet damper 13 and swinging the duct damper 12 away from the heater wall 1.

As soon as this swinging causes the nub 20 to engage the flap 1 1, the further movement of the duct dam er in the aforesaid direction causes this flap tov swing open, and the combined movements of the two dampers and i the flap continues until the damper member is halted by a suitably disposed stop, as for example by having the inlet damper 18 engage. the outer duct wall 9 as shown in Fig. 1.

Then'the heater is relatively cool, so that i the parts are in the positions shown in Fig.

7 not provided.

However, b providing this flap, and by further provic ing the spacer nub 20, 1 cause the said flap to swing ahead of the duct damper when this is approaching a nearly vertical position adjacent to the outer duct wall 9. Consequently, any such collected soot or fuel is automatically discharged from the by-pass duct whenever the duct damper opens. Furthermore, the positive spacing of the discharge flap for a minimum distance from the duct damper 12 by the nub 20 prevents sticky fiue drips from gumming this damper to the outer duct wall 9, so that I avoid the heretofore encountered interference with the free operation of such by-pass dampers.

However, while I have heretofore described my invention in connection with a brooder heater, I do not wish to be limited as to its application. Nor do I wish to be limited to the above disclosed details of construction and arrangement, since changes might obviously be made without departing either from the. spirit of my invention or from the appended claims. For example, the checkdraft chamber in the illustrated embodiment may effectively be considered as a part of the flue of the heater, and the by-pass duct as extending effectively from the ashpit to the flue.

With some heater constructions and fuels, the spacing projection 20 might be omitted, although I preferably provide such a spacer to insure a positive discharge passage between the duct damper and the flap.

I claim as my invention:

1. The combination with a heater having a by-pass duct extending from its ashpit to its flue, the said duct having an air inlet opening intermediate its height, of an inlet damper controlling the admission of air through the lower part of the said opening, a duct damper controlling the duct above the inlet damper, and a flap above the inlet damper for controlling the upper part of the said opening, the flap being movable by gravity to its closure position and movable by one of the said dampers to its open position.

2. The combination with a heater having a by-pass duct extending from its ashpit to its flue, the said duct having an air inlet opening intermediate its height, of an inlet damper controlling the admission of air through the lower part of the said opening, a duct damper controlling the duct above the. inlet damper, and a flap above the inlet damper for controlling the upper part of the said opening, the flap being movable b gravity to its closure position and movab e by the duct damper to its open position. I

3. The combination with a heater having a by-pass duct extending from its ashpit to its flue, the said duct having an air inlet opening intermediate its height, of an inlet damper controlling the admission of air through the lower part of the said opening, a duct damper controlling the duct above the inlet damper, and flap pivoted at its upper edge to the duct and controlling the upper part of the said opening, the duct damper being pivoted to the duct below the pivoting of the said flap and being disposed for opening the flap during the opening movement of the duct damper.

4. A heater construction as per claim 1, including means for affording a minimum spacing between the duct damper and the said flap.

5. A heater construction as per claim 2, in which the duct damper swings upwards towards the flap during its opening movement, and in which one of the last named two elements has a projection directed toward the other element for affording a minimum spacing therebetween when the duct damper is wide open.

6. A heater construction as per claim 2, in which the duct damper extends at an acute angle to the flap when both thereof are in their closure positions, and in which the duct damper has a projection on its upper face disposed for engaging the said flap before the duct damper reaches its wide open position during the opening movement of the duct damper.

7. In a heater having a by-pass duct-extendingfrom its ashpit to its flue and having an air inlet opening in an outer wall of the duct, a unitary double damper member pivoted intermediate of its height to the duct on a horizontal axis intermediate of the height of the said opening; the damper member comprising in rigidly connected formation a duct damper disposed within the duct and extending upwardly from the said axis when the duct damper is open, and an inlet damper depending from the said axis and disposed outside the duct and adapted to engage the outer face of the duct; a flap pivoted to and depending exteriorly of the duct from a pivot axis adjacent to the upper edge of the said opening; and a spacer interposed between the duct damper and the flap and carried by one thereof for causing the flap to swing outwardly when the duct damper is approaching the end of its duct opening movement.

Signed at Macomb, Illinois, September DONALD B. TOLLEY. 

